Aider vs Gemini CLI in 2026

Aider, Gemini CLI and AgentHydra compared on what each does for AI coding sessions, what each costs and what to check before you choose.

By SupaKeeper · 2026-10-24

SupaKeeper is published by LunarWerx, which makes some of the tools compared here.

Aider lets a developer pair program with LLMs in the terminal, and Gemini CLI is an open-source AI agent that brings Gemini into the terminal. AgentHydra, made by the team that publishes this site, shows Claude Code, Codex and OpenCode sessions in one live list. Pick by the need: pairing with LLMs points to Aider, access to Gemini points to Gemini CLI, and managing running sessions points to AgentHydra.

Option	What its sources say it does	Cost	Account or install
Aider	Pairs with LLMs to start a project or build on an existing codebase ^[1]; works with most popular programming languages ^[1]; can run in the browser ^[2]; can add images and web pages to a chat ^[1]; takes requests by voice ^[1]; connects to most LLMs ^[2]; makes a map of the codebase ^[1]	not published	not published in the facts
Gemini CLI	An open-source AI agent that brings Gemini into the terminal ^[3]; gives lightweight access to Gemini ^[3]; query and edit large codebases ^[3]	not published	Install globally with npm ^[3]; run without install via npx ^[3]; Homebrew on macOS and Linux ^[3]; MacPorts on macOS ^[3]
AgentHydra	Shows Claude Code, Codex and OpenCode sessions in one searchable list, updated live ^[4]; replies to a Claude session or several sessions ^[4]; moves a Claude chat between accounts ^[4]; shows cost by day, model, project and account ^[4]	free, no account or subscription ^[4]	Windows tray app; macOS and Linux builds not verified ^[4]; on Windows install by one-line PowerShell, GitHub Releases or Bun ^[4]

The short answer

Aider lets a developer pair program with LLMs in the terminal to start a new project or build on an existing codebase ^[1]. Gemini CLI is an open-source AI agent that brings the capabilities of Gemini directly into the terminal ^[3], and its page says it gives lightweight access to Gemini ^[3]. AgentHydra shows Claude Code, Codex and OpenCode sessions on the machine in one searchable list, updated live while they run ^[4]. Aider's own pages say it is built for pairing with LLMs across codebases, browsers, voice and editors ^[1] ^[2] ^[1] ^[1]. Gemini CLI's own page says it is the direct path from a prompt to Gemini's model ^[3]. AgentHydra addresses the sessions, accounts and costs that come with running several coding assistants day to day ^[4] ^[4]. Each fits a different question the developer is asking.

What Aider, Gemini CLI is built for

Aider is a terminal tool for pairing with LLMs to start a new project or build on an existing codebase ^[1]. It works with most popular programming languages, including python, javascript, rust, ruby, go, cpp, php, html and css ^[1]. It can run in the browser, not just on the command line ^[2]. It can add images and web pages to a chat for visual context, such as screenshots and reference docs ^[1]. It can take requests made through voice ^[1]. It connects to most LLMs for AI pair programming ^[2], and its page says it works best with models such as Claude 3.7 Sonnet, DeepSeek R1 and Chat V3, OpenAI o1, o3-mini and GPT-4o while connecting to almost any LLM, including local models ^[1]. It makes a map of the entire codebase, which helps it work in larger projects ^[1]. It automatically commits changes with sensible commit messages ^[1] and automatically lints and tests changes ^[1]. It can be used inside a favorite IDE or editor ^[1], and its documentation covers installation and getting started with pair programming ^[2]. Gemini CLI's own page describes it as giving lightweight access to Gemini, the most direct path from a prompt to the model ^[3]. The facts here offer fewer details for Gemini CLI, so this page says less about it.

What AgentHydra is built for

AgentHydra is made by the team that publishes this site. It shows Claude Code, Codex and OpenCode sessions on the machine in one searchable list, updated live while they run ^[4]. It lets a developer type a reply into a Claude session's own desktop chat, or send one message to several sessions ^[4]. It moves a Claude chat, history included, to another of the developer's accounts ^[4]. It splits a task's pieces across Claude Code CLI sessions on the developer's accounts, and moves a worker to another account when one nears its limit ^[4]. It shows cost at API list prices by day, model, project and account ^[4]. It pairs each failed shell command with the command that fixed it, and can copy those pairs out as a rules file for the developer's agents ^[4]. It lists each Claude and Codex account with its plan and 5-hour and weekly quota, and can open, focus, quit, create and delete Claude Desktop instances ^[4]. It exposes its features as MCP tools, including whoami and usage checks so an agent knows which account it is on and how much quota is left ^[4]. It packs a task and its repository into a Markdown file, leaving out common secret files, then copies a prompt and opens ChatGPT for the developer to send ^[4]. It prints the same cost numbers as JSON from the command line ^[4].

Pricing and fees

AgentHydra is free, with no account or subscription ^[4], and it is open source under the MIT License ^[4]. The facts given here do not state a price for Aider, so none is published here. The facts given here do not state a price for Gemini CLI, so none is published here. Neither set of facts describes an account, trial or discount for Aider or Gemini CLI, so none is stated here. If you need the cost of Aider or Gemini CLI for your own use, check their own pages, since the facts here do not state one.

Setting it up and daily use

Aider's documentation covers installation and getting started with pair programming ^[2], and the tool can be used inside a favorite IDE or editor ^[1]. Gemini CLI can be installed globally on macOS and Linux with Homebrew ^[3] and on macOS with MacPorts ^[3], with further install choices listed in the table below. AgentHydra's tray app needs Windows, and macOS and Linux builds exist but have not been verified ^[4]. On Windows it installs with a one-line PowerShell script, or a developer can download a build from GitHub Releases or run it from source with Bun ^[4]. Day to day, Aider runs pair programming against an LLM ^[1], Gemini CLI gives lightweight access to Gemini ^[3], and AgentHydra keeps a live list of running sessions ^[4]. The facts here say nothing more about setup or routine use for Aider or Gemini CLI beyond this, so check the tools' own pages for anything further.

Things to check before you choose

Ask which coding assistants you run and why. Aider pairs with LLMs in the terminal ^[1], Gemini CLI brings Gemini to the terminal ^[3], and AgentHydra lists Claude Code, Codex and OpenCode sessions live ^[4]. Ask which platform you are on, since AgentHydra's tray app needs Windows and its macOS and Linux builds are not verified ^[4]. Ask whether you need chat replies across sessions or account moves; AgentHydra is built for those ^[4] ^[4]. Ask how much the tools charge, since the facts here give no price for Aider or Gemini CLI. Ask whether AgentHydra's cost figures, which are API list-price estimates, are enough for your budgeting ^[4]. Ask which languages you work in, since Aider lists the languages it supports ^[1].

How to choose

If the need is pairing with an LLM to build or change code, Aider's pages describe that ^[1], including in a browser and through voice ^[2] ^[1]. If the need is lightweight access to Gemini from the terminal, Gemini CLI's page describes that ^[3]. If the need is seeing all Claude Code, Codex and OpenCode sessions in one live list, AgentHydra does that ^[4]. If the need is replying to several sessions or moving a Claude chat between accounts, AgentHydra is built for those ^[4] ^[4]. If the need is a tool that tracks cost by day, model, project and account, AgentHydra shows that ^[4]. Aider and Gemini CLI are separate tools for a developer's own coding, and AgentHydra manages the sessions and accounts around them.

Frequently asked questions

Is Aider free to use?

The facts given here do not state a price for Aider, so none is published here. Aider is a terminal tool for pairing with LLMs to start a new project or build on an existing codebase ^[1]. Its documentation covers installation and getting started with pair programming ^[2]. Check Aider's own pages if you need its cost, since the facts here give none.

Does Gemini CLI cost anything?

The facts given here do not state a dollar price for Gemini CLI, so none is published here ^[3]. Gemini CLI's page describes it as giving lightweight access to Gemini ^[3]. It can be installed globally on macOS and Linux with Homebrew or on macOS with MacPorts ^[3] ^[3]. Check its own pages if you need the cost, since the facts here give none.

Can AgentHydra work on macOS or Linux?

AgentHydra's tray app needs Windows, and its macOS and Linux builds exist but have not been verified ^[4]. On Windows it installs with a one-line PowerShell script, or a developer can download a build from GitHub Releases or run it from source with Bun ^[4]. For macOS or Linux, check whether the unverified builds cover the developer's setup before choosing it.

Does AgentHydra move chats between accounts?

AgentHydra moves a Claude chat, history included, to another of the developer's accounts ^[4]. It also splits a task's pieces across Claude Code CLI sessions on the developer's accounts and moves a worker to another account when one nears its limit ^[4]. It shows cost at API list prices by day, model, project and account ^[4].

What does Aider do?

Aider lets a developer pair program with LLMs in the terminal to start a new project or build on an existing codebase ^[1]. It makes a map of the entire codebase, which helps it work in larger projects ^[1]. It works with most popular programming languages ^[1], can run in the browser ^[2], and can be used inside a favorite IDE or editor ^[1].

Free, with no account or subscription. ^[4]

Try AgentHydra